Climate & Terrestrial Biodiversity

Climate & Terrestrial Biodiversity

Ch. 7Ch. 7

What is Climate? What is Climate?

◊ Weather - short term; today◊ Climate - general atmospheric or

weather conditions over time

◊ Weather - short term; today◊ Climate - general atmospheric or

weather conditions over time

Climate is what we expect; weather is what we get.

Climate varies over the surface of the earthClimate varies over the surface of the earth◊ 2 main factors:

• Wind - air circulation

• Ocean currents

◊ 2 main factors:• Wind - air

circulation• Ocean currents

◊ Move warm & cold moisture from one place to another, but unevenly

◊ Move warm & cold moisture from one place to another, but unevenly

Focus on AIRFocus on AIR◊ Air

circulates warmth & moisture from the tropics to other places

◊ Air circulates warmth & moisture from the tropics to other places

Focus on AIR 3 forces responsible:Focus on AIR 3 forces responsible:1. Tilt of the earth - Earth is heated

unevenly1. Tilt of the earth - Earth is heated

unevenly

Focus on AIR 3 forces responsible

Focus on AIR 3 forces responsible2. Rotation of the Earth on its axis◊ equator spins faster than

poles◊ Warm air rising over equator

goes N or S then deflected E or W◊ creates “prevailing winds” -

major surface winds that blow almost continuously

2. Rotation of the Earth on its axis◊ equator spins faster than

poles◊ Warm air rising over equator

goes N or S then deflected E or W◊ creates “prevailing winds” -

major surface winds that blow almost continuously

Quick DemoQuick Demo

◊ What happened to the line as you rotated the whiteboard?

◊ What happens to the line as you get further toward the edge?

◊ What happened to the line as you rotated the whiteboard?

◊ What happens to the line as you get further toward the edge?

Focus on AIR3 forces responsibleFocus on AIR3 forces responsible3. The water cycle ◊ heat from the sun

evaporates ocean water and transfers it to air

◊ this creates convection cells that circulate heat, air, and moisture

3. The water cycle ◊ heat from the sun

evaporates ocean water and transfers it to air

◊ this creates convection cells that circulate heat, air, and moisture

Focus on OCEAN CURRENTSFocus on OCEAN CURRENTS◊ Prevailing winds blow over ocean &

move surface water --> currents◊ Prevailing winds blow over ocean &

move surface water --> currents

Focus on OCEAN CURRENTSFocus on OCEAN CURRENTS◊ Currents move warm water to

other places • Changes vegetation & climate of the

area, especially near the coastline

◊ Currents move warm water to other places • Changes vegetation & climate of the

area, especially near the coastline

Focus on OCEAN CURRENTS Focus on OCEAN CURRENTS ◊ Continents and wind currents

shape path of ocean currents◊ Continents and wind currents

shape path of ocean currents

Focus on OCEAN CURRENTSFocus on OCEAN CURRENTS◊ Currents go clockwise in Northern

Hemisphere◊ Currents go counterclockwise in

Southern Hemisphere

◊ Currents go clockwise in Northern Hemisphere

◊ Currents go counterclockwise in Southern Hemisphere

Focus on OCEAN CURRENTSFocus on OCEAN CURRENTS◊ Also vertical mixing of water

• Cold water sinks - more dense, saltier• Warm water rises - less dense, less

salty

◊ Also vertical mixing of water• Cold water sinks - more dense, saltier• Warm water rises - less dense, less

salty

OCEAN CURRENTS + AIR CURRENTS 4EVEROCEAN CURRENTS + AIR CURRENTS 4EVER◊ Ocean currents

affected by wind◊ Heat from ocean

affects air circulation patterns

◊ Ocean currents affected by wind

◊ Heat from ocean affects air circulation patterns

For ExampleFor Example◊ El Niño Southern

Oscillation (ENSO)◊ Changes global weather

over 2/3 of the planet due to a relatively small change in wind speed

◊ El Niño Southern Oscillation (ENSO)

◊ Changes global weather over 2/3 of the planet due to a relatively small change in wind speed

So…So…◊ Air circulation + winds

+ ocean currents + continents in the way = 6 giant convection cells that shape climate

◊ (3 in north, 3 in south)◊ Warm wet air rises◊ Cool dry air sinks

◊ Air circulation + winds + ocean currents + continents in the way = 6 giant convection cells that shape climate

◊ (3 in north, 3 in south)◊ Warm wet air rises◊ Cool dry air sinks

The AtmosphereThe Atmosphere◊ Greenhouse gases warm the Earth

• H2O, CO2, CH4, N2O

◊ Greenhouse gases warm the Earth• H2O, CO2, CH4, N2O

How they workHow they work◊ Light from sun passes

through atmosphere◊ Surface absorbs heat◊ Heat radiates back up◊ Some escapes to

space◊ Some absorbed by

greenhouse gases - its good! :)

◊ Light from sun passes through atmosphere

◊ Surface absorbs heat◊ Heat radiates back up◊ Some escapes to

space◊ Some absorbed by

greenhouse gases - its good! :)

Climate Change (global warming)Climate Change (global warming)◊ LOTS and LOTS of

evidence supports the hypothesis that humans are contributing excess greenhouse gases to the atmosphere - altering earth’s climate

◊ 90-99% sure of this◊ Why not 100%◊ Precautionary Principle

◊ LOTS and LOTS of evidence supports the hypothesis that humans are contributing excess greenhouse gases to the atmosphere - altering earth’s climate

◊ 90-99% sure of this◊ Why not 100%◊ Precautionary Principle

Earth’s Surface Features also affect climateEarth’s Surface Features also affect climate◊ Rain shadow effect

• Windward side wet• Leeward side dry

◊ Rain shadow effect• Windward side wet• Leeward side dry

All of this creates BIOMESAll of this creates BIOMESHigh Mountains Polar Ice Arctic Tundra Temperate

GrasslandTropical grassland (savanna)

Chaparral Temperate Coniferous forest

Temperate deciduous forest

Tropical rainforest Tropical dry forest

Tropical Desert Temperate rain forest

Temperate desert Cold desert Taiga

Tropical and subtropical coniferous forest

Pond Inland wetlands (swamps, marshes, prarie potholes)

Mangrove forest Riparian (rivers and surrounding area)

All of this creates BIOMESAll of this creates BIOMESHigh Mountains Polar Ice Arctic Tundra Temperate

GrasslandTropical grassland (savanna)

Chaparral Temperate Coniferous forest

Temperate deciduous forest

Tropical rainforest Tropical dry forest

Tropical Desert Temperate rain forest

Temperate desert Cold desert Taiga

Tropical and subtropical coniferous forest

Pond Littoral, intertidal zone

Mangrove forest Kelp forest

Coral reef Neritic zone (coastal waters)

Continental shelf Pelagic zone (open sea)

Benthic zone (bottom of lakes and oceans)

Hydrothermal vents Cold seeps Estuaries Riparian (rivers and surrounding area)

Inland wetlands (swamps, marshes, prarie potholes)